understand the variables and types in programming


                       what does it mean by

                  VARIABLE   and     TYPE ???

Variables are simply containers for storing data values(exp : names ,numbers ,characters..etc)

Now not all the barrels have the same color ,each color refer to a certain “TYPE” of data that the barrel is designed to store

For exemple :

Explanation of the exemple : 

                                                                1-green barrel can store integers(…-3,-2,-1,0,1 ,2,3..)

                                                                2-the red barrel can store text (words , paragraphs..)

                                                                 3-blue barrel can store characters(‘A’,’B’…,’?’,’/’..’a’,’b’..)

-----------  Analogy :

A BARREL means VARIABLE

The COLOR of the barrel means the TYPE of the variable

And now let rewrite these previous phrases :

 

                                                                  1-the INT variable can store integers(…-3,-2,-1,0,1 ,2,3..)

                                                                  2-The STRING variable can store text (words , paragraphs..)

                                                                  3-the CHAR variable can store characters(‘A’,’B’…,’?’,’/’..’a’,’b’..)

 

-----------SYNTAX : 

Now let try to code an example in c#

Before we dive into the syntax word I want to mention that each variable have a DISTINCT name for it. why ? imagine if your friend doesn’t have a name then how can you call him/her ?

creating a variable in c# language :( 2 steps)

   


syntax                                                                                                     exemple                     
1 - DECLARING A variable :type variable_name ; 
2-INITIALISING a variable  (assign a value to a variable )variable_name =data_value;

Or you can mix the two steps in one line of code :

type variable_name = data_value;                                                                                    

Now you are wondering “what the heck is that semi_colon in the end of every line of code ?” 

 the answer : is exactly like the full stop at the end of the sentence . the semi colon “;” means that the command(line of code)  is done.

 

------other types of variables:

Boolean :

 the variable of type Boolean can only store one of two values {true , false} (in lowercase ,yes there is a difference between lower and uppercase in programming) 

Exp :

Now you will tell me : “hey wait ! aren't true and false  words , and we said previously that variables that store text should have the type of string not Bool !

I ll answer and tell you :”brilliant question but true and false are not ordinary words they are KEYWORDS,”

-what are keywords ?

-simply they are predefined, reserved words used in programming that have special meanings in the programming language like :

-so what happens if I wanted to use the word true or false in my text ? I can’t?

-no you can ! the thing that differentiate the text words from the keywords is just the double quotes {“”} let ‘s see an exemple 

Float :

 type of a variable that stores a number that has a decimal place

Note :

=> the first is considered as integer and the second is considered as float(3.0)

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CONCLUSION : 

variables are just containers for storing 

data ,each variable have a name and type and a value .

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Note : you should initialize(assign a value to) your variable before using it or you will get this error message :” Use of unassigned local variable” or something like it.


                  In the next devlog we will take a look of some

           operations and applications of the variables


If you have any questions feel free to post them in the comments and I ll be happy to answer them!


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thank you for reading!!!

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